Use key property from config

sbotc.1

@@ -79,7 +79,7 @@ secret-handshake protocol.
 .It Pa ~/.ssb/manifest.json
 A map of method names to method types.
 .It Pa ~/.ssb/config
-JSON file containing host, port, and SHS cap key to use if the
+JSON file containing key, host, port, and/or SHS cap key to use if the
 .Ar -s ,
 .Ar -p
 or

sbotc.c

@@ -823,9 +823,11 @@ int main(int argc, char *argv[]) {
 	char config_buf[8192];
 	len = read_file(config_buf, sizeof(config_buf), "%s/config", app_dir);
 	if (len > 0) {
+		ssize_t key_len = json_get_value(config_buf, "key", &key);
 		ssize_t host_len = json_get_value(config_buf, "host", &host);
 		ssize_t port_len = json_get_value(config_buf, "port", &port);
 		ssize_t shs_cap_len = json_get_value(config_buf, "caps.shs", &shs_cap_key_str);
+		if (key_len >= 0) ((char *)key)[key_len] = '\0';
 		if (host_len >= 0) ((char *)host)[host_len] = '\0';
 		if (port_len >= 0) ((char *)port)[port_len] = '\0';
 		if (shs_cap_len >= 0) ((char *)shs_cap_key_str)[shs_cap_len] = '\0';